/*
 * Anything: A flexible and easy to use data structure that combines the 
 * characteristics of a list and a hashmap into one data structure.
 * 
 * Based on a paper by Peter Sommerlad and Marcel Rueedi on 
 * 'Do-it-yourself reflection' entered at EuroPLOP 1998.
 * 
 * This library was written completely from scratch and is based only 
 * in spirit on the original Java Anything implementation written by 
 * Andre Weinand/Marcel Rueedi in 1997/99 and enhanced by Stefan Tramm 
 * in 2006.
 * 
 * Copyright (c) 2008 Thomas Marti and others. All rights reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package any.functor.impl.func;

import static any.functor.Functions.asIterable;

import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Set;

import any.ImmutableAny;
import any.functor.interfaces.AsSet;
import any.functor.interfaces.Function;
import any.functor.interfaces.FunctionTypedPredicate;

public class AsSetImpl<T> 
	extends BaseAnyIteratingFunction<T, Set<T>, T, AsSetImpl<T>> 
	implements AsSet<T> {
	
	private boolean ignoreDuplicates = false;

	//TODO: EnumSet??
	@SuppressWarnings("unchecked")
	public Set<T> apply(ImmutableAny from) {
		Set<T> set = createSet();
		Iterable<T> iterable = (Iterable<T>) from.give(asIterable().select(predicate).eachElement(asFunc).order(direction));
		for (T element : iterable) {
			if (!set.add(element) && !ignoreDuplicates) {
				throw new IllegalStateException("Duplicate '" + element + "' found!");
			}
		}
		
		return set;
	}

	private Set<T> createSet() {
		Set<T> set;
		if (direction != null) {
			set = new LinkedHashSet<T>();
		} else {
			set = new HashSet<T>();
		}
		return set;
	}

	@SuppressWarnings("unchecked")
	public <X> AsSet<X> eachElement(Function<ImmutableAny, X> asFunc) {
		this.asFunc = asFunc;
		return (AsSet<X>)this;
	}
	
	@SuppressWarnings("unchecked")
	public <X> AsSet<X> select(FunctionTypedPredicate<X> predicate) {
		this.asFunc = predicate.getAsFunction();
		super.select(predicate);
		return (AsSet<X>)this;
	}

	public AsSet<T> ignoreDuplicates() {
		ignoreDuplicates = true;
		return this;
	}
	
	@Override
	protected String toStringPrefix() {
		return "AsSet of type " + createSet().getClass().getSimpleName();
	}
	
}